If you are working with time or days, you can't put in a negative value because if you are doing an experiment, you can't go back in time to do that experiment to gather data. (Time for the most part considered to be an input value so that's why I used it as an example.)
No.
The distance is |-5 -3| = 8 units. (Y-coordinates are the same, so the distance is measured entirely in the x-direction. Distance is non-negative.)
Answer:
6:38am
Step-by-step explanation:
From the question we are told that
Average speed 
Distance traveled 
Generally the velocity across a distance is mathematically given given as 
Therefore
7:20-42 minutes =6:38am
An example would be:
Standard:12345678
Expanded: 10000000+2000000+300000+40000+5000+600+70+8
Word: twelve million three hundred forty-five thousand six hundred seventy-eight
